SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e343e0e8dbd7198a0a042017ed43c8854fe0bc7ba2e087ec0ead69d57af1dd1' 
  AND token = 'rFRXlQqKJsPVasuzsIMpwJ4sk5iFL3sGYI/fkknvcFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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