SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '75b8a2d435f1a5eecfd7836cda079c08d4515cbeb813467e493454cfc15b3295' 
  AND token = 'EIDguiMw9lQ+M3KBAo0Y3wlN0OVzg+ez028oAUEzBXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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