SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a487b4324925b1d0100abd4cf2708bffe520d77346c7320942510a058f756375' 
  AND token = 'b6dnEslgc9RrfJjheoOZYRkCZ9CiwjvQ/0A8mg1skQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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