SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51a8782598d87b966d8844226579171ddc9d359704b850246eb01010d152b38c' 
  AND token = '27+HyMLkamhRWjFcLPQKOmbCZVoojPW1ehVDno5Jqfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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