SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50b0da84a7feab943408791265ad0b433d03344bdf11ad9f94530fc5684eb676' 
  AND token = 'CzGD6QoPigzWx8U8fx947+6aYW2/Ty09Ty+UlRkD5fM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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