SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b45fee20c5f762ada30e7728c0410e5772676d249749b868015668db590d8ecf' 
  AND token = '16OqSZHHxjp4TJmjtzeN/VAav0gniGJaXgM6J34oB5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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