SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08438a3e2ae51fbba6599a86a18f99b9688dd9c91959163709ffd43a849c2b3a' 
  AND token = 'Puxo4r6+p4UXiHoswHNHoxc5tO8FKeHZfub9apXsZyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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