SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d3ab8822f20e8b85780e303eb7f64f03387ba9a6611e8eeb0b02ae3366da26d' 
  AND token = 'PCUY6mdg1Bk7+SwbQ/hgBg53tNdsggMkd9hcGExyq74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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