SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f39b119350c7a3513e29e862c4d9064f803e359d1224c7993879a70402de4848' 
  AND token = 'uFTyh+R6NUK08HJu8x2MCGNaEK60BAn8n+jzqziNaiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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