SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd6500187d8f959ff117c618f6f3d1d085c054c832e267553689462e85150e37' 
  AND token = 'qQzoZehJwr+oJLgxXUmGNsEgDVeMyHlAfmQFaHKcmoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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