SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7b5a04f7a7de71137dc9247824858f34d24c798ddb769f436f148a8d27afcf2' 
  AND token = 'qlBnLmN204Ovz+1J8nkhrRB3MFHPQDbBmIZHray9vKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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