SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8647ce9920842e27f3612c62b20b4c0b1b9b5b4e3dffe7a540c4754487a68762' 
  AND token = 'DqPdxitvZzqzgt8yUPo8SB3BX/aBPzCAU68M2mAXi/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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