SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5b9a650fa13d93ca77f24014f3ebba7f2231e4ba798c5cb4e30f98cc85c88c8' 
  AND token = 'pr2On+H11oq2JwswYCY9ZOnyXk/GHzI4J2GBQf/aqwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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