SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5edf725bbec191e68df6adebba427456f2cd9fbd42ceb180566b18903245a147' 
  AND token = 'dhoZxFMoK4K/fwg+zfI0VQHubkBLUmJBtB2EcgM0ApY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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