SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ea203260eb9466c2f2e0757d942ada99f81a17dbe187f230fb41d803838fbef' 
  AND token = 'gGxPFXUBWkVHtgaxH8W/yZQE7cRPPHFKs0jijYzOM3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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