SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a92337e9db73827f5e9483dedcb8edb3bd6178aa10aeda545f94f6411c93b17' 
  AND token = 'EkpDOEQfB3KjWI0ijBSYx2YUoAuglPEn6JExl6nfB3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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