SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9a910fbb930cfed69ae2a6260a32a111ddafb42c5bd364f7586373ea765eb261' 
  AND token = 'DqXLbEyHJYJkKnmM3arNprAkZ281GqJcHxLN53WXFHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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