SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ece131949e2b4f43275cc20747c8cfe92d7642ff21ba0e371e67557b2b876d' 
  AND token = 'oYxJhwD4hP/3m5o3SxqBulCy6RVUTCTgBU6FaG1msY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}