SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a88c6aea95488951f6d91ae68f6ca4459a45b123017453b2c10edd7111916154' 
  AND token = 'RprKO/8BlgWoLJ02gOdJxs+gotRQhznnD+DKVILTT/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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