SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86f543213461ede34e39c248cc157133c6ff2631ef62fedb9109761e8e68c43c' 
  AND token = 'Bn18q9Z37OYvQpSNmZOqJi7TMo/rrIPgChjSjUuLgvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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