SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e591852bbcd787115364a9f2e07062796ff0d87d76c5874950bccd01ebfe35d1' 
  AND token = 'CyMKVhRI6yR8nRdWUp6NJv/Z4YOd/0YgpSkUPT8XtV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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