SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4edb527e0cb54bf26addd5b54d01d834453fce6ec991140f39b111de73700fc4' 
  AND token = 'FeYAZxNA6hN4f8gzEODj5kjAtqATzeVOGPZMAL+tqSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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