SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bf5652ac5934b717c208d0121d37c8f9db7b07a83273c9419148660cfceef72c' 
  AND token = 'DuTP6hbdjNhH2nShs2gqQJqZFUsL3hyBUU6mywK9wqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00094

JSON explain

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