SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7488f0c0807346af9a8a0699477d4db2665ca2bb3a92075641da7c68598dd361' 
  AND token = '+RDQwEbHaGnmx0e49gox99rlPuE9BMt3w61hrYVsq0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}