SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e387cd99271bbcf508525cde12afdf44a237cd59125eb16bf1e21ccd48cd2f0' 
  AND token = 'ilJnEYO0QgBQrJxSrJjeF42IDssern01se/HsUOJHg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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