SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4a4be56712c50699dce1c56138ee4e74708e19c79991f8e4cb3430235878dee' 
  AND token = 'jIVeI8TlUvLpI9jxkcVVz1E7XKAMorA7uXB/VUQXBgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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