SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '852d65af22a8f2da5dcf9c9659736acb35de7b584fee36adbc30a7d15bea7328' 
  AND token = 'rmYQ0yBiVpxEjmFTHuCD52d2zOp//+WRXUiP6c4JbfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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