SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02a1c5051131249f5832922d2bccde8ab6c7846892b716b876f97edb437ea097' 
  AND token = '+KlSTr8ZMwLtc8WKxSj9jVLWjdYwGtVoM9SCGEH1/ZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}