SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54e06614abede15497b94f580e925747b83cb3e8430d601bf97a9b21bd4fa524' 
  AND token = 'F1hmXwMyYcyrOpWipoEWMswYAR0ctUuZyulNPTHq2aI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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