SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f70a1f23bbb12702934a9359dcb846114c140df88b444d24bb21ad42bc9de6' 
  AND token = '11rvMHnvOPfAkgKEZvAhoUYI3PXdkbBO5tUWh1AcTrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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