SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b84811612ae8f447f965683515a19fd424b73903937735b8a953965dd0e9ce69' 
  AND token = 'QjzZO34JlT7lC9qMcJglaW1Aaetp0S/RL+L/uJZNsro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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