SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82c5350d87f0a7134763eaa42a4b87e39a7fda68034ce2cc41990c3b88e9545b' 
  AND token = 'av0IfQQgVYCYKMDBIWaFV0oyn7ieur9E6rQKOnkG9C8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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