SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '87fb6142bf9533770b2b283ffebd19a2c859e2e3c4075385c49832226f0d5284' 
  AND token = '5YIsqxSdZBC1PZ86p0jpcYASJZlkrjUbBrhl0Oo9EY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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