SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a3bd5cfe1b62baf81909c5fbab7c54802f95df25be6947560dde2ec9bf9d1ae' 
  AND token = 'eWerm9TY1UwR/DKvy07hnPB2jqVqS/9tfiI0eqTo8ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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