SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9b389bb78dff2812cbc437a3728cc3664bfd2b27a94717d7e3f86477c560bc0' 
  AND token = 'V4Lfen7VZTtatBscTMSPpBZ2gUuyKH3+DwBQnXGWE6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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