SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7189bc4ef7d96b2344693184df707f183115281b9aebde565ab1057f80962c5b' 
  AND token = 'qg9a0tC2lB8RJ7ilTohcBUpgy/uWYrcXaFU7CVNJGJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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