SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55772aeaec13c2745d66ea228ad6653caddb49a8be02aa49e602bc46ba1816eb' 
  AND token = '1e/J0SOENrnspjnZlJFsuuzzQvpTIBvxoDqflF8W1Pg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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