SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c9c5adf5c13f46d60af82e6fc35b0ffa4dfa77612ed8cc5909fee78855325ea' 
  AND token = 'FCbgYbWFmwHOhtiNBW5sF3R+7qFMJHoJ8g1Ey28vBWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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