SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7db0338837ec2e79f742c59513d7a950836b1609a69f4e16204047f1fecaa15b' 
  AND token = '6hH8nXyYI86ed/FErETy1LjkWdCjgW4a2Ffohx3Rha4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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