SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '608edd9dc2bb1c69af477bf661c1c6fab6ffef7a67933af663b604df1c27b80f' 
  AND token = 'fkapfL/+QxZkTjWT43/theJd5LSlxqMu6UsiTFaROJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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