SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1fe99df232ba082f979b86eccf6bb295c4b47ed700cbd815c8c82cc90a91946' 
  AND token = 'sMASxexlMZYtH/8q9/zd0eYQYFbtXvjJi0hiFdac4AU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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