SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '136a55c509b4dc21d9a6bc73d6045f8226fc5cedbe7f4a30e28dac7a2e8f0db6' 
  AND token = 'LI148Prt4tm9d8xaSz5YZT6TSmpuSC9LLNDfRIBU6Xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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