SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7783d0bfe398391487017a682d080fd63f63afbd099808d1c23bccf0d125a2d7' 
  AND token = 'oorSZGxo1rwXlQp7bTEh/IRT+u2Ob4CmDY5xjY1dD3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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