Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf3c97ef5e9ed1734356ef0a2b2b35fe04227d1fa292b6f8decd0c1948a47bfa' 
  AND token = '+bOwtd/jUfb3t1sYpQhEehCrcvTR7mfYXWPjrbnhFw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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