SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fb51c0bd6eef6e63d4595c9fc48527ff235f4a1a2359f40a932c9be4890eaed' 
  AND token = 'cziz3lXrfmtoJAdIToR4nZrSptkNJI8HJViNcFXUd4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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