SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6c5d660b85b923266b3a19c9b50c3405c2b9da1f945951e6ad3ef5e6c937bf7' 
  AND token = 'nZHqD74UJhfnvmzOVMxPPaz3AKHE/isW/+Nxbq+VAfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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