SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7df16170a1f8783f36e524ee0a6d42154519903fd864ce70398cb9b2c3bfdaf4' 
  AND token = 'heqoTmPctI45RTywd55s9fTSKvQ6JqTByUQkyVAJGgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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