SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a019ee3204f179f60d82c38eea4400071b0fd11f6c083057f41b24a3f3c9c0d3' 
  AND token = 'G/f2M5r7Ije3qIqDccTnmYFw5PmLBTxbbNRO3gGPPHc=' 
  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"
    }
  }
}