SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e001553458706426138cd593acd698c269404051897554dee240835ef029de26' 
  AND token = 'o7L+VeVqko1mtHRuGiR6MRmIt9OmjeytC2ERSOEUi/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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