SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55daac6c35e9ce21cbed189219e7259ca5fad825c8d94319aa5b0313b81fc684' 
  AND token = 'fo1zKiPbofxkYG3bYbnT8BiRPinowMYUAzKVRk28lIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}