SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8397963695d07f5275e1006c71b96a26f20091427dafa0816548d923c4fc7fd' 
  AND token = '+i66TqUKwJQp4UF+jzZq5niSB10E2U+yHO7/SuZH7Mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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