SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cf7d99aba862da39644bfec8825f7a2d96053b205adc64d995de8fb6762166b' 
  AND token = 'KwzbJsuxlYgH+ISeOnKc9zftj/VGmndlVo9GDxd3Lao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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