SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0fa50a0069c48b39332908b163322a009565802362a0f7569fbef64b4afc071' 
  AND token = 'CqObDGHMaICooY2KSVPz+m10UGknhZ9313WkthOCRLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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