SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c268f42d24d98ed9cf03afe239bcdd44a36820e55647e951812bb5ac45907d2' 
  AND token = 'E/PK2rz1lYoaHi/FqfSkJsqAdtknjH2dLR6CLZngdL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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