SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9e1a8135f5880ef1592e167b04136f2c3aa293dd584c5dca3346415c1061e05' 
  AND token = 'y0byiyt6Zs44EWWj+YyhhDoP35XgBfjsZaYXNxF7heA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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