SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ea81741647a94617a069ffebb15c82133a3277723104f48d10f9ce866bcef357' 
  AND token = '/oQM6huCPaYPdIDi0vEHmQNZNZeNYLAcnHv1XMgA96c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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