SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '108f353372ad148e227a074eeb4735d425676cd2bdfd2aa7318709336d5d3c48' 
  AND token = 'W1j1TuW0Hvt4C+LlEN2hGzdd7kwRO2fuRjz4eAucxTA=' 
  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"
    }
  }
}