SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '689de4c857800cc8b2ee3328e6e253959f9780820250c8be094eee541982060b' 
  AND token = 'DwGlc4jXi60cEV2xJc3uUgDOHg9YBvrCM5ywYSlQxCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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