SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e49f7671a42c034be474691d36f4e85f02fc08096f1dfddcfe90c33f25939a9' 
  AND token = 'mAzOJKWMRo3tROQDoOJOvagubYDrH6zSVFlNP6jhfWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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