SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c5b6ee27ccbf49cdd70766a5260a437a6c14f7e26bc49af0ea30d8f4193cace' 
  AND token = 'RgZDHtM0UvPXcJLg/5RAsjKfkE7SlaLbcEWdjfghozU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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