SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '121ae82f78d6703c9ef8bbcd402bc657d3073bdba691ddebe856799651758a8d' 
  AND token = 'GcG6IE4aTJTcuVvF/xSwGGhIuLGAY4n1zLxpuaHhRB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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