SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18cddd56385f5408ad3b617baf330f15e2421c3f3d91bd53f9a11250807623fe' 
  AND token = 'oYrC/AZoBpvABCJ9FIETFpXt3kB39EytLZyK5yfY4Ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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