SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6dbaff55693aadd64d5cdb145dd0ed1caeea82f792dbcf8da7e5eeb89ddce68' 
  AND token = 'vy8h71lcFPF4V1+PprySDt2L+38VI1eJVd+SUt8ldKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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