SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e599481de980e3bc5a88f38f948c5d54e08ad72a74da5cf14590cf52d357ef1' 
  AND token = 'M6wQ3nuyXW0MdgQRuAvTWjIC4y8tQmyuEo7CHSrEP/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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