SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '778626bd62d02608fc5e486a82a7e5d96379ade2494b51dc9e1508254763212b' 
  AND token = 'TtuWbNnq4QhqZUQKgYL+6/gZZNnuFp58LR+K2nrbzpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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