SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '876ef04f2a5d31c36eaa2fc0ab1ee26e3d955d8adec522f413653049f0420dfd' 
  AND token = 'RovmoFoNKqZGJb9BLBdj5tVy34Rl6tSIDJctPdTD0pI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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