SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '20ced75b13f7854ccd9c303487f7ce65456dfe990af777454a31b59446598726' 
  AND token = '1bM+veNUQNu/rwFEakletVVPufAN2vGXTu8MTYj3/kY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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