SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9645b53bc47e8510ec61f2dd1c7a7fd74c550325f7ba8c2302f7c20873423fbd' 
  AND token = 'PW27nOAOz3sbRDmu7PTgasX6/MEpEHVAaM0a3ErDwA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}