SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '874d219f18b6c16d825a3fa467167164b8410365420d39b803fcbe358d9760a9' 
  AND token = 'upZMkVMkL3rIKpKS5AqUzVB/W86WImwfRldU3Yi/loY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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