SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a540560587d252db92791d4a3e5bab5b9f1973f0f728196523eb1d187454df10' 
  AND token = 'Ogv5AEJp56Z06mf9N73nj0JUN3DcVN8yGnFYpzF6eEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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