SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adc9896b905dc36e0df2accb58afc2743d2b8f43d995c9514f4a4306c9524b37' 
  AND token = '7LuqAPJ3qwH1C4/YdzU85jODiTF7MPHvDw4poYCW5ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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