SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0de2c8c1407b92838d678101cb081de4f02c0e56a8854e3616875cb4f66215c' 
  AND token = 'gRFM0YAD9sdk/B8KD4qwkd/ZpAfoaK/th2H0GQOtYho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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