SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58d2931af1c2226a72b30170992707db0e1cee8213276838b0dd711ba95b14b0' 
  AND token = '+uXREIrCweegczJcfzzOIiiMTMjhAKo9iHcFuU4LF/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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