SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ea55dcf3dcbead3e485e6e3132276bf91e1412b0942a58c38ba57d09f560277' 
  AND token = 'nCI5KI5MEgq+p4JM6d3qiu2nz7xmqGj4fRyT/aFohNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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