SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afb6f796cd19c558c586d82259554890771c357f953bf1aadc3740affc296731' 
  AND token = 'BNKelZqQRH1FI3rFhuzIQJ0CGmRkqHZKhB9xWTQOIfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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