SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '317eeaa437e7fd6dd81e8c440423a11626172ea1213678398efb014bff949289' 
  AND token = 'P1jzmABvo4tadDwmZA1oq+SyB8pAjqyJXgohJkKgJYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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