SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93549dc6e0b73347604a0864bb7ab7813d0824f58ce3ae07447946fea99c7d84' 
  AND token = '//xbHr6qs/1eAtjGYfQ+iefUh4XxVQaoTjpr4f9YHNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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