SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c49df33bec9aa4000524fee93c857f4fb850ebfa8619b4f4a72e3991e20be82' 
  AND token = 'anx23q3aO+x0LUZv7mVtWwT47/3qa+yJCr+/gGS5/sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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