SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9a1f60b582608992069d1c49a09935cb94fb254082ca56f2ce3e54e047d7ae2' 
  AND token = 'iLa+sQR/UEzh30jd6/JUmB0oCgUf/frHnhiwoH+4WgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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