SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc7268037e895375e67b61368a3292ee0f0ba86d64523a1ad662d49309dbd4b6' 
  AND token = 'bNRX3T1ShgjZIpdJ+PeDIqUU0wVjUczgHdcUrBSzhLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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