SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dc4937f3974568b871cb59f21674d2276db00e80ce4c9d7e60cf93c6b202fa8' 
  AND token = '0H0r37SFgD4hAaaNQdnXSivQdEwlsfXxX1PpCbBwP0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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