SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db4c959e875bc227c3923afb5add2a18be5cb09d54adab2dba5fde032c14252c' 
  AND token = 'Dzyf1qgm7snf5KhB792lDoFSoWqhpW8O2YR3yOLOr90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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