SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce1ac57fbf746791b0d65812e3cb9097a55c7a3f81234c986843629138810c0f' 
  AND token = 'e5nisIzEyWsDkEPSnapQttFwe9NSU94VlSwtlKKTs2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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