SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12e25c25b8a9cdac24d059e14bbc2ec92cc957c7200e5779bee2130a02fa1c3b' 
  AND token = 'AUejrrUxBksLz+g5WnMJYaBixWLl227dmSGONRUpXyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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