SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1627297b53417a482952a93b50402690662c5ab63dc736afec2e26d6f4a6cf6f' 
  AND token = 'cVpySgEXuZ5SmaVXbY7n7S2n2F3MUuTf+5sBSUoz6Ok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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