SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f939e5423dd6bddfcce0f87f20f4f251792136038f5c59cc3c36c0075dcbffa7' 
  AND token = 'xWkktZUPtT0XnZr2xqQqBEzYgZFmZocl8oCVFccRyBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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