SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8328e1a97cd94a6230a41f72be97bf6945768bb6f1a2289359ef51d6840625f7' 
  AND token = '1J+qy5vgvVzu8UgwDIL3g3S2+/Yc2k3G+zjEqqmt2/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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