SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ef7e1d1f11135ba3a9dbb573baf323434fe20dc8dfe58df9728c014833d824a' 
  AND token = 'TWQwpoH2JVwI62FIbPSQpSw0CiIJc5I3DEOxuhaLRHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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