SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '850859fec047d23972106ddfb896a010474c72870c37811615708b110d773a09' 
  AND token = 'pQrjNu3EFV/Wg80BScctfTi3x/6SNaNflQAyknX/9pY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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