SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab98d9853fec11df995c2d2fed864ae220282f516651f923069f6684405754b3' 
  AND token = 'KkzBvvVU4avuuCdOJXNaVkbgZC2dkKOu4oRt7K5qDUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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