SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fc36dca81e6ba41af3c68aec0d6481aae0d18d491842aa60f220c37245ec445' 
  AND token = 'UR30HjMgvBGeXsfSKz8UQIP4/3FsgtbngZRly4+OWDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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