SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '977b4a5a1b53016605522697cde701591c4c3d89a89fbcbee3d306d0172c2691' 
  AND token = '1JYYFda2D/UZRfrVhJPKISrkTKm+MUwWQlNwF5bAFqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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