SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e3a048330760cad559d6092f2c503b71c2f54de1c0f2c28975d1b0b21648002' 
  AND token = '/Yhu9nu6+d5pGD/bDxiYsHplurjuvGYZOj4p/hQJXIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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