SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54676f12fcfa71ac09438ecb0c511ca6e1a66b01c701434996b6dface875ec7f' 
  AND token = 'N66+uv53pwvqpgKroVe8EIBAxmnCCvgRwe8MWQpOJn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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