SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc9c6036162d57036cc8c8041b8461624c39781b5298ca3d709d466923df80be' 
  AND token = 'dnV9qDHKul05vNnrkCZWcUSooQDR5Z2zi+ZdGYvIJfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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