SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ff900e5641149eadfc54003eee4e9f0e3d4cd38753a3b8c2a9c355d0d2593ab' 
  AND token = 'qm/MWb7WVH13E+9lDjFAvTpkjfNATtI7DAH0IEE/Ym4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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