SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1fd544c1d379271e9c5aaf7c7b8760da6834978145a4b8f98829b7aeb7ff0d15' 
  AND token = 'vLJEQ+JS8oDSrp8rSmDJx5g+0pZ1Qa9KNE60wvUWhm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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