SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b771b1f7117f0d690e5ffb9e99d7758f4223eb5d00aa64c355581b46108928ff' 
  AND token = 'CAPXpQBPFuXsU39XovjHtnlVRz0oEv74cGCgNoIA/9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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