SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '780c5533adc5a8d8d483a03b8e769d142796933d5202f36ddec232014d493932' 
  AND token = 'jO21gtjYD3rIWRqiD1UDYRgL48mK+lY9svGjfGAaBVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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