SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9dd782a5ae6301ea126152bcb86a6986e042c327b322053c3422f7c5de32b82' 
  AND token = 'iS7nnvUkVNsnYB9NVYoIByzObC2Y3zeXgi99cmXpUe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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