SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7ec1e8f2bedc13e82808aac66677397cc596452166b0f0f48c961f3737e2f07' 
  AND token = 'rG+OwBNf7goo5hzCf6g1hLm4LVr+rj8XoK5HQjj1l5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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