SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4682fca9052e40385a36556a0472aafe45d0169b55e8e93a13d5e8871365ec44' 
  AND token = '5sQI/CdH++lRu1YTI1zM30UYnBgLVCobnFqbHRevilM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

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