SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce618f5fdd878659abcdbca396684b14f1eaae111a986898f9c87c580410cc58' 
  AND token = 'e7bmsnM+nLx99V7gapL2d4KmKZRs5cVth9vOsshsbN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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