SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '76d10371425c77c51fbe66e7ef3bd718bb53ea919add93d2569e7c2283660e1c' 
  AND token = 'YxCunFZG5OZGNjqm1z5maQmN72kHQBS//u3RiesJ/Bo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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