SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7251b24e8a2b6811c99ce38c5e53e0980bbe6ee135cc74f1fc67a5f410f3acda' 
  AND token = '+/5qWgfXr6hj1xFahmpizHa16vUQcCMQKPAeiAE5vdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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