SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3e59ed884a9446a2a90fd03c212750c44b8ecd0002dc560f32ee308b414cd323' 
  AND token = 'BcKHBmt+Pmo2MifMvnv9uMmBYrbki5upXttZ1HQQJpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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