SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bce0ba58700b962880ad70c5ce11a92eac0be58154d532703a83a9832241d975' 
  AND token = 'wMrFBm0Zvf99eCSmEPHAtwRZNA2RFNluGvG00kZ7FM8=' 
  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"
    }
  }
}