SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8e335a21cc5886907a13d4c7a6be4db4b7f0216b97dbce41af2c8d67f6e386b' 
  AND token = 'kO85yUaFRuS/cRyQk9OIfGPOvKgvEr7no99JW4YkZT8=' 
  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"
    }
  }
}