SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '264d78017150eb6a880072154f151b407d5388f151e752cb95ab70fa7082dc1e' 
  AND token = 'mdLuBXjlXtnvDgXGHZqpsCOEHrOHDhCDrTRTouLvSGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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