SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ea842dc300f427e614acf073dcc6f1cf630d66b7274150e6352de49eecdb84cf' 
  AND token = '/MFokW4D9g54hT42fiqHW7/CCmQCsoVzkTdYEmGKVhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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