SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de8a9e1c6c0f0fbb2ce7ebf24ad6bba1ff35225523898b6534b85a0cbb315d47' 
  AND token = 'LzmUYRq1IQw2kU+TdVpHqG3I64MimSMkex5PEqhgHcc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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